Tocotrienols may improve cardiometabolic health, for rats at least

Delta- and gamma-tocotrienols may be more effective than alpha-tocotrienol and alpha-tocopherol in attenuating metabolic syndrome, suggests a recent study in diet-induced obese rats.

Data published in the European Journal of Nutrition​​ indicated that delta-tocotrienol improved inflammation, heart structure and function, and liver structure and function in obese rats. Gamma-tocotrienol produced more modest effects, while alpha-tocopherol and alpha-tocotrienol produced only minimal changes.

Researchers from Australia and Singapore also reported that the oral absorption and distribution of alpha-tocopherol, alpha-, gamma-, and delta-tocotrienol to plasma, heart, liver and adipose tissue.

“Only delta-tocotrienol enhanced glucose metabolism associated with obesity, although both gamma- and delta-tocotrienols improved cardiovascular structure and function, and reduced adiposity,”​ wrote the researchers, led by Prof. Lindsay Brown of the University of Southern Queensland, Australia.

“These effects may be associated with the sympathovagal balance and reduction in proinflammatory microenvironment, which may differentiate the biological functions of tocopherol and tocotrienol homologues. Their distribution to vital organs is an important prerequisite to biological activity of the tocotrienols.​

“Hence, increasing intake of delta-tocotrienol and, to a lesser extent, gamma-tocotrienol may serve as a complementary dietary strategy in managing metabolic syndrome.”​

Supplement details​

Vitamin E is a family of eight separate but related molecules: four tocopherols (alpha, beta, gamma, delta) and four tocotrienols (alpha, beta, gamma, delta). While alpha-tocopherol is found in most multivitamins and is supplemented in foods, a growing base of evidence suggests that this popular vitamin E interferes with the uptake and function of tocotrienols. Tocotrienols are derived from three major sources, including rice, palm and annatto.

The current study used alpha-tocopherol provided by Sime Darby, alpha- and gamma-tocotrienol from DavosLife Naturale supplied by Davos Life Sciences, and delta-tocotrienol from DeltaGold 70 supplied by American River Nutrition.

This study was funded by the Strategic Research Fund of the University of Southern Queensland.

Study details​

Prof Brown and his co-workers gave rats a high carb high fat diet to induce obesity with accompanying cardiac remodeling, insulin resistance, hypertension, and fatty liver. Animals then received oral alpha-tocopherol, alpha-, gamma-, or delta-tocotrienol at 85mg/kg/day, corresponding to a 60kg human dose of about 800mg/day.

Furthermore, only delta-tocotrienol affected important markers of metabolic syndrome and diabetes by enhancing glucose metabolism and improving insulin sensitivity, while reducing lipids and abdominal adiposity. The mechanism of action appears to be reduction in organ inflammation, especially of the heart, liver, and abdominal fat.

Notably, the study measured vitamin E isomers in the plasma, heart, liver and adipose tissue. Although alpha-tocopherol and alpha-tocotrienol were the only isomers found in the plasma, all isomers were found in vital organs, with tocotrienol concentrations being highest in the adipose tissue. The researchers noted that, “delivery of oral tocotrienols to vital organs is the key determinant of the overall efficacy of oral tocotrienols in these tissues, rather than the concentration in plasma.”​

‘Unique study’​

Commenting on the research, Dr.Barrie Tan, president of American River Nutrition Inc. said: “The uniqueness of this study is the availability of individual isomers supplemented to animals to distinguish their distinct properties, and apply them to a very current concern of obesity and metabolic syndrome.​

“This study found that delta-tocotrienol had the strongest effect and to a lesser extent, gamma-tocotrienol with little effect for alpha-tocotrienol and alpha-tocopherol; these effects were described as ‘markedly’, ‘modest’, and ‘minimal’, respectively.”​